(Smith gives 10...Be7 with 11. Rac1, Ne5; 12. Nxe5, dxe5 (12...Qxe5; 13. f4, Qc5+; 14. Kh1 and White has a winning game), 13. Bd2 with more than enough for the pawn. However, 10...0-0; 11. Bb3, Rd8; 11. Na4, Bd7 gives Black an edge.)
11. Bb3
(After 11. Rac1, Nde5; 12. Nxe5, Nxe5; 13. Nd5? [13. Bb3=] exd5; 14. exd5? [After 14. Rd5, Black has the advantage.] 14... f6!? [14...Be7; 15. Be7, Ke7; 14. f4, Qc5+ Black wins.] 15. Bd2, Qd8; 16. f4, Bg4; 17. Qe4, Bxd1; 18. fxe5, fxe5; 19. Rxd1, Be7; 20.Rf1, Bf6; 21. Bd3 [Frankle-Brill, Atlantic Open, NY, 1973], Qd7; White does not have sufficient compensation for his sacrificed material.
11...Nde5; 12. Nxe5, Nxe5; 13. f4!? h6! 14. Bh4
(Black is attaining the strategic goals of his innovation. He has already traded off a pair of knights without, as in Smith's line, getting doubled pawns. He has prevented the board from opening up so that White hasn't been able to capitalize on his lead in development and develop an attack.
Now, after driving away White's black-squared bishop, Black intends to complete his development and castle, remaining a pawn up.
14. fxe5? hxg5; gives black the open h-file, e.g., 15. exd6, Qc5+; 16. Qf2, Bd6; with a positional and material superiority for Black.)
14... Ng6?!=;
(Here 14...g5! 15. fe5, gh4; 16. ed6, Bd6! 17. Qg4, Qe5; 19. Qh5, b5; Black has the edge.)
15. Bg3, Be7; 16. f5, Ne5; 17. Rac1?
(17. fxe6, Bxe6; 18. Bxe6, fxe6; 19. Qh5+, g6; 20. Qh3, Kf7! gives Black an edge, with an extra pawn in the endgame, but 17. Be1! creates equal chances.)
17...0-0; 18. Qh5?
(18. Bf4 is better.)
18... ef5!?
(18...Bg5! 19. Rc2, ef5; 20. Be5, Qe5 gives Black a greater advantage.)
19. Nd5?!
(White goes down fighting. If 19. exf5, Bg5 and 20...bxf5 wins. But 19. Bf4, ef4; 20. Nd5, Bd8; 21. Be5, de5; 22. Qe5, Bg4 is better, although Black still has the big advantage of the exta pawn.)
19...Bg5; 20. Rc7, f4!
(Winning a piece, and the game, due to the threat of 21...Bg4, trapping the Queen.)
21. h3, fxg3; White resigns.